Carburetor



HU HU Qw April 28, 1925.

F.H.ROYCE CARBURETOR Filed May 14, 1924 Patented Apr. 28, 1925.

lJjNrrl-:Dy STATES PATENT OFFICE.

FREDERICK HENRY' ROYCE, OF DERBY, ENGLAND, ASSIGNOR TO ROLLS ROYCE LIM-ITED, F DERBY, ENGLAND.

cnmaonnroa.

Application led- May 14, 1924. Serial No. 713,285.

To all whom it may concern:

Be it known that I, FREDERICK HENRY ROYCE, `residing atDerby, England, asubject of the King of Great Britain and Ireland, have invented certainnew and useful Improvements in Carburetors, of which the following is aspecification.

This invention has reference to an improved carburetor.

One of the difculties in an internal combustion multicylinder engine isto evenly distribute the fuel to all the cylinders ow ing to the fuelbeing deposited on the walls of the induction pipe. The object of thisinvention is mainly to overcome this diiiculty and generally to producean improved carburetor.

In a carburetor `made according to my invention the fuel is mixed with asmall quantity of air drawn from a diffuser nozzle, preferably anautomaticvariable nozzle, and before any further admission of air to themixture the latter is heated with a view to vaporizing the fuel, and tosuch vheated mixture the desired quantity of air is subsequently addedbefore admission to the induction pipe.

With such a mixture, even if the vaporized fuel is recondensed intheinduction pipe it will be in such fine particles that it will becarried in the current' and will not be deposited. What has been calleda diffuser nozzle is that more commonly termed an airvented nozzle, inwhich the orifice which determines the amount of fuel is placed belowthe maintained level'of the constant level chamber and discharges into achamber which communicates with the nozzle and 40 with the atmosphere,-so that when the asso-y ciated engine is in .operation a mixture of airand fuel commonly termed an emulsionl is discharged from the nozzle intothe I main air passage.

In the accompan drawings an example of my invention is illustrated.

Fig. 1 is avertical section of the carburetor, `lfig.r 2 a lan view withtheupper part removed an showing the vaporizer in section 4online 2.4-2of4 Fig. 1 and Fig. 3

isapart-sectional elevation on line 3- -3 of Fig. 1 viewedfrom theright. Y

` In said-drawings c1 aFiand @a indicate three members harmingv the mainbody of,

5 the carburetor, the members a? and c, being threaded and screwedtogether at ai* and the members a2 and a3 being connected together bymeans of bosses a5 formed on each of them with registering holestherethrough through which are passed bolts as secured by nuts a".

The upper portion of body member 0.1 is of larger diameter than theremainder and is threaded at its upper end where it is closed by thecover 0x12 secured by nutals and this upper portion forms a chamber(hereinafter ,called lthe piston chamber) in which slides a pistonhereinafter described, 414 indicates an annular row of holes to admitair pressure for the purposes herein after explained. The lower portionof the body member o1 has circumferential ports al equi-spaced aroundit. rlhe body member a2 has an expanded or enlarged portion L22 throughthe wall of which are formed circumferential equi-spaced ports (1.23;and

below said enlarged portion L22 and on the side remote from theinduction pipe hereinafter referred to, the said member a2 is formedwith a double wall, theinner part a24 of which forms a portion of thewall of the main air passage or conduit a (Fig. 3) to which air isadmitted vial the ports a2 and the ports al (when open).` A separate airconduit via ports 01.23, which is never closed, is also formed as aresult of the double-walled construction mentioned. indicates the upperend or head of a tubular space or passage which extends through thelower portion of `body member a2 and through the body member a3 toconstitute and receive certainpassages of the nozzle and the nozzlevalve; the said upper end or head being utilized as a connecting means,as hereinafter explained.' w28 indicates a tubular member extending fromand com` municating with the'head a of the aforesaid space or passageand havingja iange am formed "thereon, r and e?" indicates aninternally-threaded orifice"opening outv lof the side of the tubularmember a.

Referring tothe body member a", m31 `indicates the tubularv space orpassage referred to, and as an lannular air space' inldirectcommunicationwith fthe'l conduit a and communicating, via thecircumferential row of holes a, with an annular spacca around the tubec. asf indicates a'tubular projection from the member a* having a flangea formed thereon 'and vcontaining the choke tube a?" and the nozzle heador nozzle proper 01 hereinafter described. a indicates a threaded holeto receive the nozzle 010.

b indicates a chamber heated by the exhaust gases of the engine andconnected at two suitable places to the exhaust system by the pipes b1and with a flange b2 formed thereon. bs indicates a perforated platehaving cylindrical projections around the edge of each hole and carryinga system of four tubes b4, each tube opening at one end into the tubularprojection L35 and at the other end into the/tubular projection a2?. Twoof said tubes are bent laterally as shown in Fig. 2, to prevent themfrom being shielded from the hot gases by the other tubes. The chamber bis secured to the plate b3 by means of registering holes through'theflange as and a plate having studs b5 passing therethrough and securedby nuts h6. The plate 3 is secured to the tubular projections a and a bymeans of similar holes through the flange b2 and plate b3 with studs 57therethrough secured by nuts bs.

The nozzle is constructed as follows: c indicates the tube previouslymentioned, which isformed with an annular groove o1, threecircumferential rows of holes c2 o3 and `et, with arestrictedfor narrowpart o5. c6 indicates` a rod sliding in the interior of the tubecentralized or located by bushes c7 and 0"- and fitting the restrictedpart c5 of the tube c and (except as hereinafter explained) .blockingthe passage of fuel therethrough.`

The bush c" also shuts ofi the upper part of the space or passage a fromthe tube. 0S indicates a number of elongated tapered grooves formed inthe rodcfsaid grooves increasing in depth from the top downwards andbridging the restriction a so that the area of the fuel passage past therestriction is dependenton the position of said rod which is controlledas hereinafter explained. c indicates a cap screwed into and closing thelower end of the space or passage w31 and 01 the head ot' the jet havingorifices c and screwed into the hole a.

l indicates a two-diameter cylindrical member sliding in the bodymembers a1 and a2 said member d having an internal thread at each end.d1 indicates a dished diaphragm having a circular externally threadedflange d2 screwed into the member d, and d3 is an annular groove in thewall of member d, a circumferential row of holes d4 being providedthrough the wall. (Z5 indicates two other annular grooves in the wall`of the member al, and al another diaphragm curved from its centreupwards and outwards with an externally threaded flange Z7 at its upperend screwed into the member d. d is a tubular member or elongated sleeveconnect. ed at its lower end by means of a ball-andsocket joint all tothe valve rod and at its upper end by a. ball-and-socket jointd11 to athreaded rod d which passes through a hole in the diaphragm all and issecured bya nut Z13 (by means of which theposition of the grooves in thevalve rod relative to the restriction c5 can be adjusted) and a lock nut14. d indicates a helical spring to prevent slack in the connection, andd1 is a helical spring re-acting between the cover a12 and the diaphragmd1.

e indicates a nipple formed with a flange to bear against, and a threadto'screw into, the threaded orifice a2".

f is a blind tapered hole bored in body member a3, and f1 is an openingfurnished with a nipple f2 let into the throttle cham` ber, whilst f3 isa conduit connecting the top of the float tank with the hole f* indi-Cates a hollow valve having holes f5 through its wall and actuated bythe lever f6, which is under the control of the' driver of the vehicle.yf7 indicates a spring to hold the valve f6 in position, and;t8 acalibrated plug screwed into a hole opening into the conduit f3.

g indicates the float chamber and g1 the conduit therefrom to the nozzlewhilst h is the throttle chamber, and h1 a perforated flange with whichthe carburetor is bolted to the induction pipe.

The operation of the carburetor is as follows When the engine is at restthe parts are in the positions shown in the drawings and the level offuel in the tube c and annular space a84 is as shown. When the engineisl turned over, partial vacuum is produced in the throttle chamber viathe nipple e, tubular member (128. system of tubes 6*,'tubular member a,choke a", (hence past the orifices of the nozzle head 01) annularchamber (L32, conduit 126 and the ports a. The suction of air past thenozzle orifices sucks the fuel via the nozzle head, annular space 01.and holesnc2 from the tube 0 and at the same time sucks air through thesame passages via holes 03, annular space a, holes w33 and chamber a3.The mixture of fuel and air issuing from the nozzle head 'passes throughthe system of tubes in the boiler along the tubular member a to thelhead a of' the tubular space or passage a the holes d, groove d andclearance between the body member al and flange Z2 to the pistonchamber, whereby the said diaphragm d1 is lifted against the action ofthe spring di by air pressure through the holes a, which lifts the wholeof the member d, uncovering ports a, and at the same time lifting therod 0"', bringing the large area of the tapered grooves c 3 level withthe restriction c and thus increasing the flow of fuel.

'.l`l1e tension of the spring d, the shape and size of the ports al; andthe shape ofA the grcmres c* are all proportioned so that at all speedsand throttle openings the desired ratio of fuel and air will beattained. The depression in the throttle chamber isl to some extent and,if desired for mixture adjustment purposes, communicated to the floatchamber and the various parts adjust ed accordingly. The extent to whichsuch depression is communicated can be varied by the driver by means ofthe valve f4.

lVliat I claim as my invention and desire to secure by Letters Patent ofthe United States isz- 1. In a carburetor, a body member cornprising twocylindrical elements, one within and tting the other, the outer memberhaving an enlarged part provided .with ports, the inner element alsobeing provided with ports, means forming an air passage leading from thespace between said elesupply flowing through the ports of both elementsand a-subsidiary air supply through the ports of the outer element andsaid passage;

2. In a carburetor, the combination of a nozzle, and a device forcontrolling the supply of fuel thereto; said device comprising 'asuction-operated piston, an axially-movable valve rod, a sleeve betweenthe piston and valve rod, ball-and-socket joints connecting the adjacentends of the sleeve and said piston and rod, and a spring within thesleeve to prevent slackness of said joints.

In witness whereof I have signed this specification.

FREDERICK HENRY ROYCE.-

